This updates `org-ctags-tag-regexp' to avoid adding broken entries for
radio targets in the TAGS file.

With the old regexp, org-ctags would add radio targets to the TAGS file
with an extra angle bracket at the beginning.  So a target of
"<<<radio target>>>" would be entered in the TAGS file as
"<radio target", instead of just "radio target".

This meant that when you click on the linked text "radio target", the
link wouldn't match any of the TAGS file entries.  So org-ctags would
inquire about rebuilding the TAGS file.  Then, when it still couldn't
match the target, it would attempt to be helpful and ask about adding a
new target to the end of your org file.  Only after you declined that,
it would finally allow Org-mode to move point to the radio target as
intended.

This patch allows radio targets to coexist with org-ctags and to even
use them with org-ctags in external files, in the same manner as
dedicated targets.

-- 
Best regards,
Martin Marshall